OBJECTIVE: To investigate the suitability of measurements of mercury (Hg) concentration as a means of identifying patients with health complaints attributed to dental amalgam. METHODS: Hg in erythrocytes, plasma, urine, and saliva was determined in 27 patients complaining about health problems attributed to amalgam, 27 healthy volunteers with amalgam fillings, and 27 healthy amalgam-free volunteers. RESULTS: Concentrations of inorganic mercury in blood and of total mercury in urine and saliva differed significantly between individuals with amalgam fillings and amalgam-free volunteers, but not between symptomatic patients and healthy volunteers with amalgam fillings. Urine Hg levels tended to be better correlated with blood than with saliva data. Levels of organic Hg were equal in all groups. CONCLUSION: Concentrations of total and inorganic mercury in body fluids do not distinguish between asymptomatic amalgam bearers and those who suffer from a poorly defined syndrome of multiple nonspecific symptoms.